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Roland EF-303

Groove Effects (1999)

electronic musical effect

"Dj-oriented machine with step value modulations inspired from analog sequencer.
The EF303 also includes a V.A digital drum machine and a TB -303 emulation"

 Main Data 

technical data

Company: Roland
Model: EF-303
Class: effect module
Dates: 1999
Technology: digital effect
Synthesis: Virtual Analog
Resolution: 20 bits
Sampling rate: 44 kHz
Algorithms: 16 models
Sequencer: 16 steps
Tempo: 40 to 240 BPM
Sync: Midi clock
Memory: 16 slots
Tuning scale: 21 models
Midi: IN / OUTs
Price: 250€

EFFECT MODULE Main panel features a segments display, 16 sliders, 7 knobs and 30 buttons.

Rear panel terminal connectors:
- Midi interface
- RCA stereo outputs
- headphones
- microphone input
- line RCA input switch between line / phono with ground terminal for turntables.
- ac Power supply is a 9V external DC PSU negative polarity -)+


- No official VST plugin
- no known samples library

Have some EF-303 sample set you want to share? CONTRIBUTE :) 

owner's manual download

service manual download NOT AVAILABLE

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 EF-303 In details 

edit function panel

Internal DSP resolution works at 20 bits / 44 kHz sampling rate.  

The EF-303 groovebox is a fully digital unit which manages 3 main sound sections: described in details below:

modulator levers control

1 - Modulator effect Mode

The 16-steps fx modulator is especially designed for real-time visual performance. The principle is quite simple: the step modulator cyclically changes the effect settings to a specified values and creates moving textures or rich rhythmic patterns (It is also possible to set the number of steps for a sequence, up to 16 at 480 ticks per note resolution). Modulator motion can be played in 5 modes:forward, backward, pendulm, random and forwardbackward.

drum machine editor

2- Virtual Drum Machine

The virtual Drum  on modelling virtual analog.
Drum Patterns are recorded using the step modulator.  Each step slider is split into 5 equal zones and each of them corresponds to a specific percussion between 5 percussions:
- muted (no sound)
- open hihat
- closed hihat
- snare drum
- bass drum.

Bass liner editor

3- Tb303 Emulator

Alsoa  virtual analog and emulates the iconic TB-303 bassliner: notes are entered using the step modulator sliders from bottom position for lower octave to higher, in addtion the bassliner has some sonic controls including filter cutoff, resonance and slide emulation (but no accent "twang").

Ef-303 Modulator Algorithms

1filterclassic cutoff filter with resonance and a digital LFO
2isolatorboosts or cuts specific frequency ranges on 3 bands low / med / high
3flangerclassic short delay metallic effect with LFO modulation 
4pan delayecho with panning ping-pong effect
5reverbadds classic reverberation
6pitch/delayshifts the pitch and adds a time delay
7slicer/pantremolo effects with stereo panning variation
8compadds dynamic compression
9LO-FIreduces sound quality lowering the sampled BIT depth (bit crusher)
10ring modis a digital ring modulator 
11phaserphase shifting effect with own LFO
12voiceformant pitch shifter as voice changer, ROBOT for synthetic voice
13Vo Moduse input to modify the internal synth generator
14Syn+DLYplays a lead sound + delay effect
15Syn Bassplays a bass sound
16Syn Rhythmplays the rythm sounds

Clock and Sync


SYNC internal frequency range is from 40 to 240 BPM or defined by TAP button. The sync function provides 12 tempo dividers: 16th, 16th dotted, 8th, 8th dotted, quarter, half note, whole, 2 whole notes, four whole notes, 16th triplet, 8th triplet and quarter note triplet.

MIDI synth and drum can be triggered by Midi and EF-303 knobs do transmit Midi CC#.

MEMORY features :
- 16 setups that can be data dumped to Midi sysex.

- 21 tuning scales : chromatic, diatonic, minor, dominant, whole, pentatonic and more.

Roland EF303 battery replacement

Our Verdict 

" EF303 is original and fun for original textures !  "





Quality / 



- drums and tb are average
- no CV sequencer options


- idea
- real time edit

Are you an EF-303 user? do you like it? You do not agree with our review?  Let us know in the comment field just below 



Ef-303  gallery

Fun Vid demo from Japan :) 

Roland EF303 Roland EF303
80 out of 100 based on 1 user ratings
200 to 250 from 1 sellers Sellers: